On September 24th, Indian troops from the Strategic Forces Command tried to launch a Prithvi II ballistic missile. The motor began burning fuel, but not enough to get it off the launcher. There was lots of smoke and confusion, but no launch. An investigation is now under way.
These user trials are tests where troops from the using organization try to use a new weapon that has successfully completed testing using crews from the manufacturer. This is a common practice, but particularly necessary in India, where the manufacturers often cut corners during development and testing. The troops on the military launch crews are usually not privy to these workarounds, and the developers sometimes just keep their fingers crossed that the troops can handle things on their own. For example, last year, the first user test of the ground launched BrahMos cruise missile failed. Not a major problem, it turned out. After a few months, everything was put right. This will probably be the same deal with the Prithvi II.
It was last year that India conducted the first successful test of this new, longer range version of its Prithvi II, and the missile successfully hit a target 350 kilometers away. This launch was to test the ability of the missile to carry a half ton warhead. This is the minimum size for a nuclear warhead. India will take 5-10 years to develop the miniaturized warheads Russia and the United States developed in the 50s and 60s. This version of the Prithvi is a strategic weapon, since it can put nuclear warheads on major targets within neighboring Pakistan.
A larger, 5.6 ton, Prithvi III is in development. This missile can carry a half ton warhead 600 kilometers. Ten years ago, the best a Prithvi II could do was 250 kilometers with a quarter ton warhead. The increase in range and warhead weight for the Prithvi III was achieved by using a solid fuel rocket motor, and adding a second stage with a liquid fuel motor. The Prithvi II uses a liquid fuel rocket.
Prithvi missiles are used, in slightly different versions, by the army and air force. The basic army version has a range of 150 kilometers (and a one ton warhead), while the air force versions can go 250 kilometers (with a half ton warhead). The Prithvi is a ballistic missile that reaches its target within 5-10 minutes of launch. The missile uses liquid fuel, meaning it takes up to an hour to ready for launch. Over a hundred missiles have been delivered so far, with all the recent production being the 250 kilometer version.
The Prithvi missile carries cluster bomb or nuclear warheads. Accuracy is thought to be quite good, using software correction and GPS to achieve under fifty meter accuracy. The missile, with non-nuclear warheads, would be used against high value targets like headquarters or fuel and ammo depots. Test firing of the Prithvis are held regularly, for training and quality control purposes.
The original Prithvi missile was 23 feet (7.5 meters, 8.5 meters with some larger warheads) long, had a circumference of 9.3 feet (3 meters), and weighed 3.5 tons (4.1 tons with larger warheads). With the "standard" 250 kg (550 pound) warhead, range was 250 kilometers. A one ton warhead reduced range to about 80 kilometers. There are six conventional warheads available: high-explosive/fragmentation, anti-personnel/vehicle submunitions, incendiary submunitions, runway cratering munitions, FAE (Fuel-Air Explosive) and earth-penetrating bunker buster.